V. Rajakannan

Structural studies on three plant diterpenoids from Leonotis nepetaefolia

This paper describes the interesting structural studies on three new diterpenoids (plant products), namely, hydroxy-dialactone nepetaefolinol (9,13-epoxy-6β-hydroxy-8α-labdane-16,15 :19,20-diolactone), dehydrated nepetaefolinol (9,13-epoxylabd-5-ene-16,15:19,20-diolactone) and isomeric tetrol (15,16-epoxy-labda-13(16),14-diene-6β,9,17,19-tetrol: which is the reduction product of new diterpenoid leonotinin) isolated from Indian herbal plant Leonotis nepetaefolia (collected in the flowering season from Guindy area, Madras), and are found to be the major compounds in their extractions, so they are expected to possess the interesting pharmacological properties. In all three structures, the fused ring systems adopt distorted chair-chair, distorted chair and intermediate between 1,2-diplanar and half-chair and chair-chair conformations. In compounds 1 and 2, the twisted form of lactone rings are orthogonal to each other and make dihedral angle of 88.4(1) and 87.5(2)° with each other. The primary interaction between the molecules is van der Waals in nature.

The crystal structure of 4-(2-chlorobenzyl)-5-phenyl-1,2,4-triazole

The crystal structure of the title compound [CCDC No. 157498],

Crystal Structure of Dimeric Cu(II) Complex {μ,μ'‐acetato O,O bis [N‐salicylidene‐2‐amino‐pyridine‐methanolato N,N,O]} : perchlorate

C_1_5H_1_2N_3Cl

4‐Acet­amido‐2‐methoxy‐5‐[3‐(phenyl­sulfanyl)indole‐2‐carbonyl]­benzoic acid

, contains a 1,2,4-triazole moiety substituted with a phenyl ring and methyl chlorophenyl group as exogenous substituents. The triazole ring is planar within 0.004(3)A. The dihedral angles between the phenyl rings and the 1,2,4-triazole ring are 88.1(1)° and 44.3(1)°. The interplanar angle between the two phenyl rings is 57.2(1)°. The packing of the molecules is stabilized by the intermolecular interactions.

Phyl­lanthin from the plant Phyl­lanthus amarus

The crystal structure of the title complex has been solved using X-ray diffraction data. The compound crystallizes from aqueous ethanol solvent in the triclinic system, space group P-1, with unit cell parameters: a = 8.9532(1), b = 12.7423(3), c = 14.9012(3) A, α = 73.767(1), β = 75.322(1), γ = 77.496(1)°, Z = 2, V = 1559.4(5) A 3 . The trial structure was determined by automated Patterson methods and subsequent difference Fourier techniques using DIRDIF98 and refined to a final R-factor of 0.064. The copper ion Cul adopts a (4+1) square-pyramidal geometry defined by the tridentate N-salicylidimine dianions and the neutral monodentate pyridine ligand in the basal plane. The apical position is occupied by a solvent methanol molecule at a distance of 2.341(4) A. The copper Cu2 adopts a square-planar geometry.

Crystal structure analysis of 5‐amino‐7‐(pyrrolidin‐1‐yl)‐2,4,4‐trimethyl‐1,4‐dihydro‐1,6‐naphthyridine‐8‐carbonitrile

In the title compound, C25H20N2O5S, the indole ring system is planar. The dihedral angles between the indole moiety and the two substituent aromatic rings are 73.6 (1) and 44.4 (1)°. The structure is influenced by intramolecular O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds and the crystal structure is stabilized by intermolecular N—H⋯O hydrogen bonds and C—H⋯π and C—H⋯O interactions.